Hi,

We are about to start design work on a replacement of some code and I was wondering if anyone had any advice...

The situation is this: we have a client-server application. Client side is a Delphi application and the back end is made up of a number of Perl scripts that are showing their age and are become more difficult to maintain as time goes by.

The acutal details of what the application does is somewhat beside the point but the process is basically this:

1. User request operation through Delphi UI.
2. Parameters for the specific type of job is written by Delphi into a series of tables in a database.
3. Depending on which operation is requested one of a number of Perl scripts is started on the server.
4. The parameters for job are read from the database.
5. Data is extracted from source database into temp DB.
6. Series of queries are executed against the database to generate temporary tables.
7. Further queries are run against these temporary tables to get some statistics.
8. Based on the result further queries may be run.
9. User is informed of completion.
10. User views results via Delphi application.

At the moment each of the operations has a specific script that implements the series of actions that make up the job. These actions are things like:

• Create table
• Delete table
• Run action query e.g. insert into
• Run select query and apply transform to value or values in return set and store in temp table
• Run singleton select query and store values for future refence
• If .. then .. else based on the previously stored results
• Write log file entry
• Send progress indication back to user via database and client

As you can imagine these scripts are somewhat difficult to maintain/extend.

We are currently thinking that a better approach would be to extract the logic of each of the operations and implement an engine to execute an abstract definition of the job.

Couple of questions:

• Is this a good approach?
• Is there any existing modules/techniques that we could use to implement such an approach?

Regards.

---

---

Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!

Titles consisting of a single word are discouraged, and in most cases are disallowed outright.

Read Where should I post X? if you're not absolutely sure you're posting in the right place.

Please read these before you post! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

Posts may use any of the Perl Monks Approved HTML tags:

a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr

You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)

	For:		Use:
	&		&
	<		&lt;
	>		&gt;
	[		&#91;
	]		&#93;

Link using PerlMonks shortcuts! What shortcuts can I use for linking?

See Writeup Formatting Tips and other pages linked from there for more info.